What is Creutzfeldt-Jakob Disease?

Creutzfeldt-Jakob disease (CJD) is a rare, degenerative, invariably fatal brain disorder. It affects about one person in every one million people per year worldwide; in the United States there are about 200 cases per year. CJD usually appears in later life and runs a rapid course. Typically, onset of symptoms occurs about age 60, and about 90 percent of individuals die within 1 year. In the early stages of disease, people may have failing memory, behavioral changes, lack of coordination and visual disturbances. As the illness progresses, mental deterioration becomes pronounced and involuntary movements, blindness, weakness of extremities, and coma may occur.

There are three major categories of CJD:

In sporadic CJD, the disease appears even though the person has no known
risk factors for the disease. This is by far the most common type of CJD and
accounts for at least 85 percent of cases.

In hereditary CJD, the person has a
family history of the
disease and/or tests positive for a genetic mutation associated with CJD. About 5 to 10 percent
of cases of CJD in the United States are hereditary.

In acquired CJD, the disease is transmitted by exposure to brain or nervous
system tissue, usually through certain medical procedures. There is no evidence
that CJD is contagious through casual contact with a CJD patient. Since CJD was
first described in 1920, fewer than 1 percent of cases have been acquired CJD.

CJD belongs to a family of human and animal diseases
known as the transmissible spongiform encephalopathies (TSEs). Spongiform refers
to the characteristic appearance of infected brains, which become filled with
holes until they resemble sponges under a microscope. CJD is the most common of the
known human TSEs. Other human TSEs include kuru, fatal familial insomnia (FFI),
and Gerstmann-Straussler-Scheinker disease (GSS). Kuru was identified in people of an isolated tribe in Papua
New Guinea and has now almost disappeared. FFI and GSS are extremely rare
hereditary diseases, found in just a few families around the world. Other TSEs
are found in specific kinds of animals. These include bovine spongiform encephalopathy (BSE), which is found in cows and is often
referred to as “mad cow” disease; scrapie, which affects sheep and goats; mink
encephalopathy; and feline encephalopathy. Similar diseases have occurred in
elk, deer, and exotic zoo animals.

Mad Cow Disease (BSE) Link to vCJD

variant Creutzfeldt-Jakob disease (vCJD)

There exists strong epidemiologic and laboratory evidence for a causal association between a new human prion disease called variant Creutzfeldt-Jakob disease (vCJD) that was first reported from the United Kingdom in 1996 and the BSE outbreak in cattle. The interval between the most likely period for the initial extended exposure of the population to potentially BSE-contaminated food (1984-1986) and the onset of initial variant CJD cases (1994-1996) is consistent with known incubation periods for the human forms of prion disease.